In the same period – from July 9 to July 15 this year – 39 people died of pneumonia, the department’s weekly morbidity report showed.

However, heart disease was only the fifth leading cause of ailment in the city, with 120 recorded cases.

Pneumonia ranked third, with 218 recorded cases.

"Three out of 100,000 people have heart diseases based on the overall incidence rate. District 2 has the highest rate at 11 cases," Dr. Ed Serrano, officer-in-charge of the Division of the Preventable Diseases, said.

Bronchitis remained on top of the morbidity list in Manila with 234 cases, followed by gastroenteritis with 227 cases, Serrano said.

However, he said no death was reported due to bronchitis or gastroenteritis.

Tuberculosis was fourth on the morbidity list with 147 cases, the Manila Health Department report said. Tuberculosis cases increased by 9 percent compared to the number of recorded cases in the same period last year, the report said.

Serrano said bronchitis and gastroenteritis cases actually decreased by 19 percent and 16 percent respectively as compared to same period last year.

"The overall incident rate of bronchitis in the city is 16 per 100,000 population. District 1 has the highest number with 28 cases. In the same district, 19 of every 100,000 population contracted gastroenteritis," he said.

As the flu season has begun, Serrano assured that there is no cause for alarm, saying that contagious respiratory diseases have never been the leading causes of morbidity cases despite the increase in the number of influenza cases compared to the figure during the same period last year.

Meanwhile, city health officials recently issued a health advisory on flu symptoms. They include high fever, sore throat, runny nose, headache, body aches, tiredness, diarrhea, vomiting and difficulty in breathing.

Serrano said a person afflicted with flu must cover his nose and mouth when sneezing to prevent direct transmission.

Health experts said flu has an incubation period of five days during which the infected person can transmit the virus to another person.